Field of the Invention
Embodiments of the present invention relate to an electrically conductive contact point pin and a charged particle beam apparatus, and, for example, relate to a contact point pin used as an earth pin which prevents charging (electrification) of a substrate when the substrate is irradiated with electron beams.
Description of Related Art
The lithography technique that advances miniaturization of semiconductor devices is extremely important as a unique process whereby patterns are formed in semiconductor manufacturing. In recent years, with high integration of LSI, the line width (critical dimension) required for semiconductor device circuits is decreasing year by year. For forming a desired circuit pattern on such semiconductor devices, a master or “original” pattern (also called a mask or a reticle) of high accuracy is needed. Thus, the electron beam (EB) writing technique, which intrinsically has excellent resolution, is used for producing such a high-precision master pattern.
An exposure mask substrate is fabricated by writing a circuit pattern with an electron beam onto a mask blank where a Cr film (light shielding film) and a resist film are, in order, formed on a quartz glass substrate, and performing development and etching of the light shielding film so as to form a light shielding film pattern (mask pattern). When a pattern is written by an electron beam writing apparatus, charging of the resist film occurs due to irradiation of the electron beam. Because of the charging of the resist film, the trajectory of the subsequent electron beam is bent, thereby becoming difficult to write a pattern with highly precise dimensions. Therefore, inhibiting charging of the resist film is performed by breaking (rupturing, fracturing) the resist film to insert an earth pin into the underlying conductive film, such as a Cr film, in order to execute earthing for inhibition of the charging (e.g., refer to Japanese Patent Application Laid-open No. 2012-015331).
With recent micropatterning, it is examined to form a dense insulating film layer on the light shielding film, which is different from the conventional way, in order to improve the etch resistance of the light shielding film when a mask pattern is formed. However, there is a problem in that since a dense insulating film has a high tensile strength, it is merely deformed and not broken even if the load to a conventional earth pin is increased, thereby being difficult for the pin to reach and enter the underlying conductive film. This causes difficulty in sufficiently inhibiting charging of the resist film because it is impossible to insert the earth pin into the conductive film to make it earthed. On the other hand, if the load is further increased, it may lead to a new problem of breaking the quartz glass substrate so as to generate particles. Such a problem is not limited to the mask substrate, but may similarly occur, for example, in the case of writing a pattern by directly irradiating a semiconductor substrate with an electron beam. Further, the problem of not reaching the underlying conductive layer because of not being able to break the insulating film may also occur, for example, in the case of measuring a resistance value of the conductive layer under the insulating film of the semiconductor substrate as well as in the case of earthing.